Towers are the most important component of the overhead power transmission line system. When failure occurs, direct and indirect losses are very high; hence accurate prediction of tower failure becomes very important for the reliability and safety of the transmission system. One cannot accurately predict the behavior of tower after practical loading conditions, so testing of tower for various loading conditions before installing in field becomes very important. The present paper discusses the structural behavior of towers during full scale testing carried out at Central Power Research Institute, Bangalore, India. Although, the towers were safe for various loading conditions based on the design/analysis, during full scale testing, different types of premature failures were observed. Necessary modifications in towers have been carried out and these towers were retested successfully. The details of remedial measures / strengthening of members carried out during testing are brought out in this paper.